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     var orgin = 100;  
     var num = prompt('请输入您要的操作:\n1.存钱\n2.取钱\n3.显示余额\n4.退出');
     while(num!=4){
        if(num=='1'){
            var save = prompt('请输入你要存的钱数')
            orgin+=Number(save);
            alert('您现在存的钱数是：'+orgin)
        }else if(num=='2'){
            var drawMoney = prompt('请输入你要取的钱数')
            orgin-=Number(drawMoney);
            alert('您现在存的钱数是：'+orgin)
 
        }else{
            alert('您现在存的钱数余额是：'+orgin)
        }
        var num = prompt('请输入您要的操作:\n1.存钱\n2.取钱\n3.显示余额\n4.退出');
        
     }
     alert('您正在退出！')
     
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